Conjunctival characteristics in primary open-angle glaucoma and modifications induced by trabeculectomy with mitomycin C: an in vivo confocal microscopy study

Objectives: To evaluate the microscopic epithelial features seen with in vivo confocal microscopy (IVCM) of bulbar conjunctiva in glaucomatous patients undergoing trabeculectomy with mitomycin C in order to elucidate modifications. Methods: Fifteen eyes of 15 consecutive Caucasian patients affected with primary open-angle glaucoma (POAG) undergoing trabeculectomy and 10 eyes of 10 glaucomatous patients (controls) under medical therapy were enrolled. Eyes were examined using a digital confocal laser-scanning microscope (HRT II Rostock Cornea Module) at baseline and after 6 weeks. The mean microcyst density (MMD: cysts/mm(2)) and microcyst area (MMA: mu m(2)) were the main outcome measurements. Results: Before surgery, the mean intraocular pressure (IOP) was 25.1 (SD 3.2) mm Hg. MMD and MMA were 22.4 (11.9) and 4696.0 (3608.1), respectively. After trabeculectomy, the mean IOP was 16.1 (1.7) mm Hg. A marked increase in both MMD and MMA, with values of 103.1 (22.6) and 29 489.3 (12 954.9), respectively, was observed. In the control group at baseline, the mean IOP was 15.7 (1.9) mm Hg, and the microcyst parameters did not differ from eyes undergoing filtering surgery. After 6 weeks, IOP and microcysts parameters did not show any significant modifications. Conclusions: Conjunctival epithelial microcysts were demonstrable in glaucomatous eyes under medical therapy prior to trabeculectomy. The filtering procedure increased microcysts density and surface at bleb site indicating a marked postsurgical enhancement of aqueous filtration across conjunctiva.